The present invention relates to fabricating sliders for use in a disc drive actuation system. In particular, it relates to fabricating sliders with slider bond pads located along a top surface or sides of a slider body.
Air bearing sliders have been extensively used in disc drives to position a transducing head above a rotating disc. The transducing head is typically carried by the slider. Conventionally, head positioning is accomplished by operating an actuator arm with a large scale actuation motor, such as a voice coil motor (VCM), to easily position the slider over a track on a disc. Typically, disc drive systems include a suspension assembly attached to the actuator arm for supporting and positioning the slider. The suspension assembly includes a load beam attached to the actuator arm and a gimbal disposed at the opposite end of the load beam. The air bearing slider carrying the transducing head is mounted to the gimbal. This type of suspension assembly is used with both magnetic and nonmagnetic discs. The VCM rotates the actuator arm and the suspension assembly to position the transducing head over the desired radial track of the disc.
In order for the disc drive to read and write data from the transducing head, conductive traces are disposed along the suspension assembly for the disc drive to electrically communicate with the slider. The traces extend along the gimbal and end at flex on suspension (FOS) bond pads formed adjacent to the slider. Sliders typically used in disc drive systems have slider bond pads disposed on a trailing edge of the slider such that an electrical connection can be made between the traces and the slider. Typically gold bond balls are used to provide the connection between the FOS bond pads and the slider bond pads.
The slider bond pads are typically placed at the trailing edge of the slider because it is easier to access this part of the slider during wafer-level fabrication of sliders. However, difficulties have arisen with the current sliders using slider bond pads on the trailing edge, in particular with aligning the slider bond pads with the FOS bond pads of the suspension assembly. Misalignment of the two sets of bond pads degrades the connection between the FOS bond pads and the slider bond pads.
One alternative to forming the slider bond pads along the trailing edge of the slider is to place them on the top surface of the slider (opposite the air bearing surface). Top surface location of the bond pads improves the head gimbal assembly such that it is easier to align and connect the FOS bond pads with the slider bond pads, rather than matching up the FOS bond pads with the small, vertical surface of the trailing edge. In addition, there is more surface area on the top surface to locate and form the slider bond pads.
The slider body is typically formed during slider processing from a wafer comprised of a multi-layer substrate. Once the slider assembly features are fabricated, the substrate is sliced along slice lanes, or rows, into a plurality of slider bars. Each slider bar includes a plurality of individual sliders. The slider bars are cut along a plurality of dice lanes extending across the wafer substantially perpendicular to the slice lanes, to differentiate the individual slider bodies. Fabrication of the slider features, including the top surface slider bond pads, occurs at the bar-level after the substrate has been sliced into slider bars.
Some disc drive actuation systems include a microactuator to finely position the transducing head over a track of a disc. The density of concentric data tracks on magnetic discs continues to increase, requiring more precise radial positioning of the head. The VCM provides large scale movement of the transducing head, but lacks sufficient resolution to effectively accommodate high track density discs. Thus, a microactuator is used to finely position the transducing head and accommodate the more densely space tracks.
One design of a microactuator is transducer-level microactuator, which is built into a slider and moves the trailing edge of the slider carrying the transducing head. In transducer-level microactuators, an alternate position is need for the slider bond pads at a stationary portion of the slider. The trace cannot be bonded to a moving portion of the slider. Thus, top surface slider bond pads or bond pads located on a stationary portion of the slider are desired.
Fabrication of slider bond pads on the top surface of the slider is typically done at the bar-level, which is less efficient and more costly than wafer-level fabrication processes. A method is needed in the art for fabricating sliders having slider bond pads on the top surface, or an alternative surface besides the trailing edge of the slider. The method should be efficient and cost effective, and preferably a wafer-level fabrication process.